Interferon alpha, beta Receptor Chain 2, Fc Chimera, Recombinant, Human (IFNabR2)

IFN-a/b R2, also known as IFNAR2, is a 100 kD glycoprotein in the class II cytokine receptor family. These proteins form heterodimeric receptor complexes that transduce signals from the interferon, IL-10, and IL-28 families of cytokines. 1,2 IFN-a/b R2, in association with IFN-a/b R1, is required for mediating the antiviral, antiproliferative, and apoptotic effects of the type I interferons IFN-a and IFN-b. IFN-a/b R2 is the principal ligand binding subunit of the receptor. Ligand binding is stabilized by the subsequent association with IFN-a/b R1, resulting in the formation of a signaling ternary receptor complex. Mature human IFN-a/b R2 consists of a 217 aa extracellular domain (ECD) with two fibronectin type III repeats, a 21aa transmembrane segment, and a 251aa cytoplasmic domain. Alternate splicing generates a secreted isoform that corresponds to the ECD and a 50kD transmembrane isoform with a substituted and truncated cytoplasmic region. The short isoform is impaired in its ability to activate signaling molecules and functions as a dominant negative receptor subunit. IFN-a/b R2 is also subject to presenilin-dependent intramembrane proteolysis, resulting in the liberation of nearly the entire ECD as well as the cytoplasmic domain which migrates to the nucleus and can inhibit gene transcription. , High concentrations of soluble IFN-a/b R2 bind and neutralize IFN-a and IFN-b, while lower concentrations prolong the antiviral activity of circulating IFN-b but not IFN-a. Human but not mouse IFN-a/b R2 constitutively associates with STAT4, which may account for species specific differences observed in type I interferon responses. 12 Within the ECD, human IFN-a/b R2 shares 63%, 60%, and 48% aa sequence identity with bovine, mouse, and ovine IFN-a/b R2. Source: Recombinant corresponding to human CD33 (aa 1-16), human IFN-a/b R2 (aa27-243), IEGRMD linker and human IgG (aa100-330) expressed in mouse NSO myeloma cells, Molecular Mass: The recombinant human IFN-a/b R2/Fc is a disulfide-linked homodimeric protein. Based on N- terminal amino acid sequencing, the recombinant human IFN-a/b R2/Fc starts at Ile 27. Each monomer has a calculated molecular mass of approximately 51.3 kD. As a result of glycosylation, recombinant human IFN-a/b R2/Fc migrates as an approximately 71-76kD protein in a SDS-PAGE under reducing conditions. Activity: Measured by its ability to enhance rhIFN-b mediated antiviral activity (McKenna, S.D., et al., 2004, J. Interferon Cytokine Res. 24:119-129). The ED 50 for this effect is typically 6-30ng/mL in the presence of 0.6ng/mL rhIFN-b. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterilePBS, 0.1% HSA or BSA. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.